1. Technical Field
The present invention relates to a process for producing cyclohexanone oxime. Cyclohexanone oxime is useful as a raw material of ε-caprolactam and further, a raw material of nylon-6, and the like.
2. Description of the Related Art
As a process for producing cyclohexanone oxime, a process wherein an ammoximation reaction of cyclohexanone is carried out with hydrogen peroxide and ammonia in the presence of a titanosilicate catalyst has been known (see for example, JP-A-62-59256 (1987), JP-A-6-49015 (1994) and JP-A-6-92922 (1994)). With respect to a process for collecting cyclohexanone oxime from a reaction solution which has been obtained by the ammoximation reaction, for example, JP-A-62-59256 (1987) discloses a process wherein the above-mentioned ammoximation reaction is carried out using water as a reaction solvent and cyclohexanone oxime is extracted with toluene from the reaction solution after removing the catalyst from the solution by filtration. Further, JP-A-6-92922 (1994) discloses a process which includes carrying out the above-mentioned ammoximation reaction using a mixed solvent of t-butyl alcohol and water as the reaction solvent, subjecting the reaction solution from which the catalyst has been removed by filtration to distillation to remove unreacted ammonia and water-containing t-butyl alcohol as distillate, and extracting cyclohexanone oxime with toluene from the bottom product, and then subjecting the extract to distillation to remove toluene as distillate, and collecting cyclohexanone oxime as a bottom product.